The cytokines interleukins 1 alpha and 1 beta (collectively IL-1) play a central role in mediating immune responses and inflammatory reactions. These cytokines have been implicated in several inflammatory diseases including rheumatoid arthritis. Thus, much pharmaceutical research has been directed toward discovery of chemicals that influence physiologic effects of IL-1 either by affecting IL-1 levels or interacting with IL-1 receptors.
IL-1 receptors are specific protein molecules present on the surface of cells responsive to IL-1. IL-1 exerts its effects by binding to these receptor molecules. Molecular cloning experiments have shown the human T-cell IL-1 receptor to be a 557-amino acid transmembrane protein coded for by a DNA sequence of approximately 1900 nucleotides. Sims, J. E. et al: Proc. Natl. Acad. Sci. U.S.A. 86:8946-8950 (Nov. 1989). Similar experiments have shown the human fibroblast IL-1 receptor gene to have the same nucleotide sequence. Chua, A. O. and Gubler, U., Nucleic Acid Res. 17:10114 (1989).
The native DNA segment coding for IL-1 receptors, as all such mammalian DNA strands, has two strands; a sense strand and an antisense strand held together by hydrogen bonding. The messenger RNA coding for the receptors has the same nucleotide sequence as the sense strand except that the DNA thymidine is replaced by uridine. Thus, synthetic antisense nucleotide sequences should bind with the DNA and RNA coding for the receptors. Because the binding strength of the DNA sense and antisense strands is the total of the hydrogen bonds between the 1900 nucleotide base pairs, the binding of a short, i.e. less than 50 nucleotide, antisense sequence to the RNA coding for the IL-1 receptor would be expected to be relatively weak.
Synthetic antisense polynucleotide sequences have been shown to reversibly reduce expression of Torpedo acetylcholine receptors in cultured Xenopus oocytes. Sumikawa, K. and R. Miledi, Proc. Natl. Acad. Sci. U.S.A. 85: 1302-1306 February 1988). Antisense polynucleotide sequences also have been shown to inhibit expression of T-cell receptor expression in T-cell hybridomas. Zhenc, H. et al, Proc. Natl. Acad. Sci. U.S.A. 86: 3758-3762 (May 1989). Synthetic polynucleotides in which the phosphate group is replaced by a phosphorothioate or methylphosphonate generally have been proposed as possible pharmaceutical agents. Cohen, J. S., Trends in Pharmacol Sciences: 10(11) 435-437 November 1989).
Therefore, synthetic modified polynucleotide sequences that block expression of receptors when administered internally are needed to allow use of antisense strands as therapeutic agents. Specifically needed are polynucleotide sequences which when administered safely and effectively block expression of IL-1 receptors.